I have nothing to compare to (except ie-80 iems) and got mine he-400 today. I am happy to trade with you for few weeks. I am in UK though, so shipping costs may be slightly higher, ok with me.
I think the more experienced head-fiers have a chance to listen to both of them the better :)
I wonder if i would hear the difference between the 2, and if yes - which one I would actually prefer.
But this are the first set of big headphones for me, I've spent way too much of my time trying to decide what to get as these are not cheap. I based my choice on my prefered sound signature and opinion of experts from this forum. Now I am just afraid that I didn't get exactly what I decided to pay for. As I said these is first pair of big headphones for me, and these are very different to iem-s, so I didn't know what to expect.
My ie-80 seem darker in first impressions, but from buying iems i know i personally need to burn-in. I didn't like sm3 when I got them but they grew on me, didn't like senn ie-80 either, now they are my fav, so I know I need some hours before knowing what i think about the sound :)
Oh, I drive them with E17.